<abstract><title style='display:none'>Abstract</title>The effect of ball milling powder mixtures of Höganäs pre-alloyed iron Astaloy CrM, low-carbon ferromanganese Elkem, elemental electrolytic Cu and C-UF graphite on the sintered structure and mechanical properties was evaluated. The mixing was conducted using Turbula mixer for 30 minutes and CDI-EM60 frequency inverter for 1 and 2 hours. Milling was performed on 150 g mixtures with (in weight %) CrM + 1% Mn, CrM + 2% Mn, CrM + 1% Mn + 1% Cu and CrM + 2% Mn + 1% Cu, all with 0.6%C. The green compacts were single pressed at 660 MPa according to PN-EN ISO 2740. Sintering was carried out in a laboratory horizontal furnace Carbolite STF 15/450 at 1250°C for 60 minutes in 5%H2 – 95%N2 atmosphere with a heating rate of 75°C/min, followed by sintering hardening at 60°C/min cooling rate. All the steels were characterized by martensitic structures. Mechanical testing revealed that steels based on milled powders have slightly higher mechanical properties compared to those only mixed and sintered. The best combination of mechanical properties, for ball milled CrM + 1% Mn + 1% Cu was UTS 1046 MPa, TRS 1336 MPa and A 1.94%.</abstract>

The Effect of Powder Ball Milling on the Microstructure and Mechanical Properties of Sintered Fe-Cr-Mo-Mn-(Cu) Steel

<abstract><title style='display:none'>Abstract</title> The fields of soft magnetic composites and powder metallurgy technologies have a powerful potential to redesign the way of electric motor preparation, and will continue to grow for years to come. A design of the novel soft microcomposite material composed of spherical FeSi particles and Ni0.3Zn0.7Fe2O4 ferrite nanofibers is reported together with a characterization of basic mechanical and electrical properties. The needle-less electrospinning method was used for a preparation of Ni0.3Zn0.7Fe2O4 ferrite nanofibers, which has a spinel-type crystal structure as verified by XRD and TEM analysis. The dielectric coating was prepared by mixing of nanofibers with glycerol and ethanol because of safe manipulation with fumed fibers and homogeneous distribution of the coating around the FeSi particle surface. The final microcomposite samples were prepared by a combination of the traditional PM compaction technique supplemented with a conventional sintering process of the prepared green compacts. The composition and distribution of the secondary phase formed by the spinel ferrite fibers were examined by SEM. It is demonstrated that the prepared composite material has a tight arrangement without any significant porosity, which manifest itself through superior mechanical properties (high mechanical hardness, Young modulus, and transverse rupture strength) and specific electric resistivity compared to the related composite materials including resin as the organic binder.</abstract>

The Preparation of Soft Magnetic Composites Based on FeSi and Ferrite Fibers

<abstract><title style='display:none'>Abstract</title>The customary edged tool for machining is uneconomical for harder and hard to machine materials and furthermore the level of surface finish accomplished is not that great. As of late, a lot of consideration in mechanical engineering has been centered on finishing tasks. Not many investigations have been accounted for till date on the advancement of substitute magnetic abrasive powder (MAP). In this paper, to improve the finishing performance, the abrasive powder were prepared by mechanical alloying of diamond powder and iron (Fe) powder, compacting these with universal testing machine (UTM) and then sintered at different temperature in a sintering machine in an inert gas (H2) atmosphere. These compacts were crushed and sieved to obtain various sizes of MAP. This abrasive powder were micro-structurally examined. The results indicate that the densification increases and porosity decreases with increasing temperature. Moreover, the prepared bonded MAP has potential performance as a new MAP for fine finishing in Magnetic Abrasive Flow Machining (MAFM) process.</abstract>

Preparation, Microstructure Evaluation and Performance Analysis of Diamond-Iron Bonded Magnetic Abrasive Powder

<abstract><title style='display:none'>Abstract</title>For powder metallurgy products, high density is an essential requirements to obtain maximum mechanical properties. Here, supersolidus liquid phase sintering (SSPLS) is an effective means to attain high sintered density, as known from PM high speed steels. In the present work it is shown that this technique can also be applied to Cr prealloyed low alloy steel grades. Supersolidus sintering through indirect heating requires precise control of temperature and also the atmosphere, to avoid uncontrolled changes of the carbon level. Higher C contents are beneficial here since they enable lower temperatures and result in wider temperature windows for sintering. The temperatures necessary for SSLPS at moderate C levels are fairly high for standard sintering furnaces, therefore induction sintering was studied in this work. It showed that, as was to be expected, also here precise temperature control is required, but for any carbon level tested a sintering temperature could be identified that yielded high sintered density and good shape retention. The high density attained, in combination with the very high temperatures, results in pronounced grain growth, this process no more being inhibited by the presence of pores, which is undesirable but can however be remedied by suitable heat treatment.</abstract>

Miba Sinter Austria GmbH, Dr. Mitterbauer-Str.1, AT-4655 Vorchdorf,

Supersolidus Sintering of Cr Prealloyed Steels by Inductive Heating

<abstract><title style='display:none'>Abstract</title>Simulations are continuously becoming more and more important to predict the behaviour of materials, components and structures. Porous materials, such as PM, put special demands on the material models used. This paper investigates the application of the Gurson material model to PM steels. It is shown how the model can be calibrated to material data. The results are also applied to an indentation test, where it’s demonstrated that experimental results can be reproduced with some accuracy. Limitations of the model, and the potential to use more advanced material models are also discussed.</abstract>

Plasticity Modelling in PM Steels

<abstract>
<title style='display:none'>Abstract</title>
The tetracalcium phosphate/nanomonetite (TTCPMH) biocements with the addition of sodium alginate were prepared by mechanical homogenization of powder mixture with hardening liquid containing sodium alginate. The effect of various viscosity of different alginates on properties of TTCPMH cement mixture was investigated. The medium viscous (MED) alginate had a more negative effect on setting process and compressive strength than low viscous (LOW) alginate. An approx. 50% decrease in mechanical properties (compressive strengths, Young´s modulus, work of fracture (WOF)) was revealed after an addition of 0.25 wt % with rapid fall above 1 wt % of LOW alginate in biocement. A statistically significant difference in the WOF was found between of 0.25 and 0.5 LOW alginate biocements (p&lt;0.035) whereas no statistical differences were revealed between WOF of 0.5 and 1 LOW alginate biocements (p˃0.357). In the microstructure of composite cements, the increased amounts of granular or finer needle-like nanohydroxyapatite particles arranged into the form of more separated spherical agglomerates were observed. A low cytotoxicity of cement extracts based on measurement of cell proliferation was revealed.
</abstract>

Influence of Sodium Alginate on Properties of Tetracalcium Phosphate/Nanomonetite Biocement

<abstract>
<title style='display:none'>Abstract</title>
High entropy ceramic coatings, including multicomponent transition metal nitrides called also high entropy nitrides (HEN), are usually deposited using reactive arc and/or DC magnetron (co)sputtering. High Target Utilization Sputtering (HiTUS) was not applied in HEN systems up to now. Subsequently, the mechanical properties of HEN coatings prepared by HiTUS are also not known. The transition metals from the 4th and 5th group of the periodic table (Ti, Zr, Hf, Nb, V, and Ta) are strong nitride formers which would be the most suitable for HEN coating systems and therefore, investigation of their properties would be of significant interest. However, the nanoindentation measurements on thin coatings always produce „composite“ values involving the contribution from the substrate. The separation of the coating properties from composite values requires upgraded analytical approaches different from standard Oliver &amp; Pharr analysis. Thus, the aim work is to investigate the structure, hardness, and elastic modulus of TiZrHfNbVTa–xN coatings with different nitrogen stoichiometry deposited by reactive HiTUS using both CSM for bulk and CSM for thin films methods and to compare the results obtained on 4 different substrates (Si wafer, sapphire, 100Cr6 steel, and Ti6Al4V alloy). The subsequent results showed systematic differences in the calculated mechanical properties depending on the substrate properties both in CSM and CSMTF modes. Stiffer substrates always resulted in the overestimations of the calculated hardness and indentation modulus compared to softer substrates with lower Young’s modulus and the differences were in the range of around 10 %. Obviously, better theoretical models for the calculations of true coating properties are required.
</abstract>

Micromechanical Properties of Reactive HiTUS TiNbVTaZrHf–N Coatings on Different Substrates

<abstract>
<title style='display:none'>Abstract</title>
Although optical properties are essential for materials for optical purposes, their mechanical properties must also be considered as they directly govern their practical applicability as well as their machining. The machining of optical glasses is mainly carried out by mechanical removal of the material using free or bonded abrasives. The relationship between the local mechanical properties of three types of borosilicate glasses used to produce optical elements (mirrors) and the type of surface machining was investigated. The samples were machined using two approaches, namely 7-axis CNC surface machining and conventional manual machining. Advanced analysis of nano/micro-mechanical properties was performed on glass samples using quasi-static nanoindentation and microindentation and dynamic impact test complemented by the analysis of the acoustic emission signals generated during the mechanical tests.
The results show a difference in mechanical properties between industrial and optical borosilicate glasses. The type of machining has a strong influence on studied mechanical properties and surface quality. Glasses manufactured by CNC have more pronounced acoustic emission signal and crack more than glasses manufactured by hand. The different behavior of hand- and CNC-machined surfaces can be linked to different subsurface damage caused by different contact conditions between the workpiece and the instrument/abrasive. As a result, a different density of surface and especially (near)-subsurface flaws are present in the glass. Simax is slightly softer than BG33 glass, which together with the less pronounced AE may indicate a lower amount of subsurface cracks/damage.
</abstract>

Effect of Machining on Mechanical Properties of Borosilicate Glasses

<abstract>
<title style='display:none'>Abstract</title>
The main shape deviations of a Berkovich indenter are the indenter bluntness and indenter tilt. The influence of the Berkovich indenter tilt on the results of the FEM modelling of steel nanoindentation is evaluated in this paper. The indenter tilt has an impact on the indentation curves and contact area. The X5CrNiCuNb 16-4 steel nanoindentation was modelled by FEM and the indentation curves were obtained. The Berkovich indenter was blunted and the tilt of the indenter was changed to determine its influence on the indentation curves. The results showed that growing tilt shifts the indentation curves to higher values of indentation forces and makes unloading curves steeper which is in agreement with a larger contact area. The calculated indentation curves were compared with the experimental indentation curves and the impact of the indenter tilt to the indentation curves was determined.
</abstract>

The Influence of Tilt on Berkovich Indentation of a Steel Sample Using FEM Analysis and Nanoindentation

<abstract>
<title style='display:none'>Abstract</title>
Welding of the austenitic stainless steel AISI 304 and Ti6Al4V is complicated by hard and brittle intermetallic compound formation. In this contribution, we study a laser welding method that partially overcomes this problem using interlayer. Bronze foil (CuSn6) of thickness 100 µm and 200 µm was inserted between steel and titanium sheets and lap welds were realized on pulsed Nd:YAG laser. Representative samples were investigated by nanohardness measurement, SEM/EDS, and XRD analysis to detect the localization of the intermetallic phases. The macrostructure of the weld cross sections was displayed by optical and digital microscopy. The nano-hardness test revealed the presence of very hard intermetallic mainly around the interface between the fusion zone and bottom metal sheet. EDS mapping displayed the main elements Fe, Cr, Cu and Ti distribution in the fusion zone, EDS line scanning detected elements‘ signals in the diagonal and horizontal directions. XRD analysis revealed expected intermetallic compounds FeTi and CuTi2 and solid solution Cu0.8Fe0.2.
</abstract>

Investigation of Hybrid Lap Welds of TI6AL4V and Stainless Steel with Bronze Interlayer

<abstract>
<title style='display:none'>Abstract</title>
High entropy alloys are one of the most developing classes of materials of the 21st century. Their properties can significantly vary depending on their chemical composition and processing method. Thus, the microstructure and mechanical properties of CoCrFeMnNi high entropy alloy prepared by conventional casting, melt-spinning and mechanical alloying were investigated in this study. The observed structure and grain size were typical for this type of alloy and production methods. It was found that the hardness of the sample prepared by mechanical alloying with subsequent spark plasma sintering is higher compared to cast and melt-spun samples due to the finer microstructure and higher deformation energy stored.
</abstract>

Effect of the Processing Routes on the Properties of CoCrFeMnNi Alloy

<abstract>
<title style='display:none'>Abstract</title>
Micro-scratch test was used to evaluate the fracture toughness of the main hydration products of ordinary Portland cement paste at the micro-scale. The evaluation was done with the aid of scanning electron microscopy and acoustic emission (AE) signals. Portlandite was found to be the only phase where AE detected elastic waves due to cracking during microindentation and micro-scratch test. Such behavior simplifies phase separation during the evaluation process of the micro-scratch test. The micro-scale fracture toughness results obtained from the tests were found in close agreement with other available experiments and models in the literature.
</abstract>

Fracture Toughness of Cement Paste Assessed with Micro-Scratch and Acoustic Emission

<abstract><title style='display:none'>Abstract</title>The Sn–Ag–Cu (SAC) solders with low Ag or Cu content have been identified as promising candidates to replace the traditional Sn–Pb solder. In this study, an extensive discussion was presented on two major area of mechanical properties and microstructural investigation of SAC305 and SAC405. In this chapter, we study the composition, mechanical properties of SAC solder alloys and microstructure were examined by optical microscope and SEM and mechanical properties such as tensile tests, hardness test and density test of the lead solder alloys were explored. SAC305 and SAC405 alloys with different Ag content and constant Cu content under investigation and compare the value of SAC305 and SAC405. From this investigation, it was reported that tensile strength is increased, with an increase of Ag content and hardness and density were also increases in the same manner.</abstract>

Investigating the Microstructural and Mechanical Properties of Pure Lead-Free Soldering Materials (SAC305 &amp; SAC405)

<abstract><title style='display:none'>Abstract</title>Understanding the effect of powder feedstock alterations during multicycle additive manufacturing on the quality of built components is crucial to meet the requirements on critical parts for aerospace engine applications. In this study, powder recycling of Alloy 718 during electron beam melting was studied to understand its influence on fracture behavior of Charpy impact test bars. High resolution scanning electron microscopy was employed for fracture surface analysis on test bars produced from virgin and recycled powder. For all investigated samples, an intergranular type of fracture, initiated by non-metallic phases and bonding defects, was typically observed in the regions close to or within the contour zone. The fracture mode in the bulk of the samples was mainly moderately ductile dimple fracture. The results show a clear correlation between powder degradation during multi-cycle powder reuse and the amount of damage relevant defects observed on the fracture surfaces. In particular, samples produced from recycled powder show a significant amount of aluminum-rich oxide defects, originating from aluminum-rich oxide particulates on the surface of the recycled powder.</abstract>

Effect of Powder Recycling on the Fracture Behavior of Electron Beam Melted Alloy 718

<abstract><title style='display:none'>Abstract</title>Traditionally, powder metallurgy has been based on two major industrial sectors – ferrous precision parts and hardmetals. Both of them relied heavily on the automotive industry, with focus on internal combustion engines. Today, there is an increasing trend towards alternative drivetrain systems, and powder metallurgy faces the challenge to find new applications to replace those lost with the decrease of classical internal combustion drives. In this presentation it is shown that the main strength of powder metallurgy lies in its enormous flexibility regarding materials, geometries, processing and properties. This enables PM to adapt itself to changing requirements in a changing industrial environment. Examples given are PM parts in alternative drivetrain systems, new alloying concepts and processing routes offering distinct advantages. With hardmetals, innovative microstructures as well as sophisticated coatings offer increased lifetime, applications ranging from metalworking to rockdrilling and concrete cutting. A particularly wide area is found in functional materials which range from components for high power switches to such for fuel cells. Soft and hard magnets are accessible by PM with particularly good properties, PM having in part exclusivity in that respect, such as for NdFeB superhard magnets as well as soft magnetic composites (SMCs). Metal injection moulding (MIM) is gaining further ground, e.g. in the medical area which is a fast-growing field, due to demographic effects. Finally, most additive manufacturing techniques are powder based, and here, the knowledge in powder handling and processing available in the PM community is essential for obtaining stable processes and reliable products. Conclusively it can be stated that PM is on the way to fully exploit its potential far beyond its traditional areas of applications.</abstract>

What Will Be the Future of Powder Metallurgy?

<abstract><title style='display:none'>Abstract</title>Fused Layer Modelling (FLM) is one out of several material extrusion (ME) additive manufacturing (AM) methods. FLM usually deals with processing of polymeric materials but can also be used to process metal-filled polymeric systems to produce metallic parts. Using FLM for this purpose helps to save costs since the FLM hardware is cheap compared to e.g. direct metal laser processing hardware, and FLM offers an alternative route to the production of metallic components.To produce metallic parts by FLM, the methodology is different from direct metal processing technologies, and several processing steps are required: First, filaments consisting of a special polymer-metal composition are produced. The filament is then transformed into shaped parts by using FLM process technology. Subsequently the polymeric binder is removed (”debinding”) and finally the metallic powder body is sintered. Depending on the metal powder used, the binder composition, the FLM production parameters and also the debinding and sintering processes must be carefully adapted and optimized.The focal points of this study are as following:1. To confirm that metallic parts can be produced by using FLM plus debinding and sintering as an alternative route to direct metal additive manufacturing.2. Determination of process parameters, depending on the used metal powders (steel and copper) and optimization of each process step.3. Comparison of the production paths for the different metal powders and their debinding and sintering behavior as well as the final properties of the produced parts.The results showed that both materials were printable after adjusting the FLM parameters, metallic parts being produced for both metal powder systems. The production method and the sintering process worked out well for both powders. However there are specific challenges in the sintering process that have to be overcome to produce high quality metal parts. This study serves as a fundamental basis for understanding when it comes to the processing of steel and copper powder into metallic parts using FLM processing technology.</abstract>

Additive Manufacturing of Steel and Copper Using Fused Layer Modelling: Material and Process Development

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Powder Metallurgy Progress

Journal of Science and Technology of Particle Materials

 POWDER METALLURGY PROGRESS – international journal of powder technology and powder-derived materials.  POWDER METALLURGY PROGRESS is an international peer-reviewed...

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